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Objectives: To investigate whether frailty modifies the association of systolic blood pressure (SBP) with cardiovascular mortality and all-cause mortality in community-dwelling older adults. Design: A prospective cohort study. Setting: A population-based study of nationally representative older Chinese adults in a community setting. Participants: This study included participants aged 65 years or older from the Chinese Longitudinal Healthy Longevity Survey 2002–2014 and followed up to 2018. Measurements: Participants were divided into two groups according to a frailty index based on the accumulation of a 44-items deficits model. The association between SBP and mortality was analyzed using multivariable-adjusted Cox proportional hazards models. Results: Among 18,503 participants included, the mean age was 87.2 years and the overall median follow-up time was 42.7 months. We identified 7808 (42.2%) frail participants (mean frailty index=0.33), in which 7533 (96.5%) died during the follow-up. Effect modification by frailty was detected (P for interaction=0.032). Among frail participants, a U-shaped association was found with hazard ratios of 1.16 (95% CI, 1.02–1.32) for SBP < 100 mmHg, and 1.11 (95% CI, 1.00–1.24) for SBP ≥ 150 mmHg compared with SBP 120–130 mmHg. For non-frail older adults, a tendency toward higher risk among those with SBP ≥ 130 mmHg was observed. The analyses towards cardiovascular mortality showed similar results. Conclusion: Our results suggest the presence of effect modification by frailty indicating a possible negative effect for elevated SBP in non-frail older adults and a U-shaped relationship of SBP in frail older adults with respect to mortality even after adjusting for diastolic blood pressure. [ABSTRACT FROM AUTHOR]

Objective: To explore the relationship between overnight urinary sodium to potassium ratio and the risk of cardiovascular disease (CVD). Methods: A subsample of 10 percent of the participants (35-59 years old) from the People's Republic of China-United States Collaborative Study of Cardiovascular and Cardiopulmonary Epidemiology (prospective survey) were used. Three consecutive overnight urine samples were collected in the autumn of 1983-1984 and the spring in 1985-1986, respectively. Urinary sodium and potassium were detected and calculated for 8 hours excretion. The occurrences of cardiovascular events were recorded in 2 years interval from 1987-1988 until December 31, 2005. Participants were divided into first ratio group, second ratio group, and third ratio group based on the tertiles of sodium to potassium ratio. Cox proportional hazard regression model was used to determine the relationship between sodium to potassium ratio and risk of CVD. In addition, participants were divided into 2 subgroups by the median of overnight urinary sodium and potassium, and then combined each other for 4 subgroups including low sodium-low potassium group, low sodium-high potassium group, high sodium-low potassium group, and high sodium-high potassium group, to explore the relationship between different sodium-potassium combinations and the risk of CVD. Results: A total of 954 participants were included in the final analysis, of whom 459 (48.1%) were males. There were 318 cases in the first, second and third ratio group, respectively. There were 347 cases in low sodium-low potassium group and high sodium-high potassium group, and 130 cases in low sodium-high potassium group and high sodium-low potassium group. After a median follow-up of 18.6 (18.3, 19.3) years, cardiovascular events occurred in 81 participants, including 64 stroke and 20 coronary heart disease events. Multivariate analysis showed that comparing with the first ratio group, the hazard ratios ( HR ) in the second and the third ratio groups were 2.04 (95% CI 1.06-3.95, P= 0.034) and 2.07 (95% CI 1.07-4.03, P= 0.032), respectively. The CVD risk in low sodium-low potassium group was 24% higher than the low sodium-high potassium group (reference), but this result did not reach statistical significant level ( P= 0.685). The risks in high sodium-high potassium group ( HR =3.32, 95% CI 1.26-8.76, P= 0.015) and high sodium-low potassium ( HR =3.04, 95% CI 1.05-8.83, P= 0.041) group were both significantly increased. Conclusions: Overnight urinary sodium to potassium ratio is positively correlated with the risk of cardiovascular events. High urinary sodium plays a more important role for the increased risk of cardiovascular events than low potassium.